What factors should be considered when choosing a bearing?

There are many things that need to be considered when selecting a bearing for a given application:

  • Type of loading, such as radial, axial, or a combination of radial and axial as well as the magnitude of these loads
  • Operating Speed
  • Required Running Accuracy
  • Available Space
  • Misalignment
  • Noise Level
  • Mounting and Dismounting

Are AMI products interchangeable with most major manufacturers?

Yes,  Our products are interchangeable to other manufacturers.  Please consult the Interchange PDF found under the product resources drop down menu.

Are all of AMI's catalogued items in stock?

Yes. We actively stock all catalogued items throughout our warehouse network.

Are all of AMI's products catalogued?

No. If you can’t find what you are looking for please contact our sales department, in most cases we can accommodate your specific needs.

Can I buy direct from AMI?

AMI is proud to support and sell exclusively through a network of authorized local distributors, so to find out where to purchase our products, please visit the “Locations” page of this website.

What are your payment terms?

Payment terms are net cash within 30 days from the date of invoice. All orders are subject to the approval of our credit department.

Do you have a minimum charge?


How do I obtain a CAD drawing?

We now offer CAD drawings of all our catalogued items on our website for your convenience. The CAD drawing links are available on each individual item page of our online catalog. If you require a non-catalogued item drawing please contact our engineering department.

If I modify my AMI bearing will the warranty be void?

Yes, all modifications to a bearing once it has shipped from one of our facilities void all warranties, written or implied.

Can bearings be refurbished?

Due to their internal design, ball bearings typically cannot be disassembled to the component level; therefore they typically cannot be refurbished.

Do you carry roller bearings?

We do not carry roller bearings. Since AMI strictly focuses on mounted ball bearing units and their respective bearing inserts, we have the most diverse product offering in this market segment.

Does AMI carry stainless steel bearings?

AMI is a market leader in corrosion resistant ball bearings and offers the widest range of stainless steel bearing insert sizes as well as stainless steel housing styles.

What is the difference between a solid base and hollow base?

Solid Base Housings are manufactured with no cavities and no filling; they are stronger than hollow base and have no traps for bacterial and fungal growth. In a thermoplastic housing, a solid base won’t crumble under steam or high-pressure wash down. Hollow base saves material and weight to reduce cost. Some back-fill the hollow base with an epoxy resin to eliminate traps for bacterial growth, however this does not improve strength, can create an uneven mounting surface, and water can penetrate between the housing and filling materials which will induce cracking.

What is a high temperature bearing?

AMI uses specially heat stabilized bearing rings, greater internal clearance (C4), specially selected lubricants that don’t breakdown under high temperatures, and zinc anodized slingers. We have two basic versions of our high temperature bearings, designated with a suffix “C4HR5” for bearings that are capable of 400 °F and suffix “C4HR23” for bearings that are capable of 450 °F

When is a free spinning bearing required?

For critical applications like pulp and paper converting, printing, and packaging, where expensive downtime results from materials tearing due to excessive torque and vibration.

What factors increase or decrease bearing torque?

The two biggest factors that affect both the starting and the running torque of a bearing are seal design and lubricant selection. Shaft and housing fits, component accuracy and surface finish, and retainer design have some affect as well.

How can I keep contamination out in a high speed application?

In higher speed applications it is typically necessary to use non-contact sealing arrangements to minimize running torque and heat generation, so the use of slingers and secondary sealing arrangements are often necessary. A flowing oil lubrication system can often be the best solution as well.

Do you offer maintenance training?

Yes. Upon request we offer training sessions at no charge.

How much maintenance do bearings typically require?

Once installed properly, most mounted bearings only require periodic relubrication with a small amount of grease and a check to ensure they are running cool, quiet, and with sufficient accuracy.

How long will my bearing last?

This depends on many factors such as applied loading conditions, operating speeds, duty cycles, temperatures, and the operating environment. Some basic information is provided in our Technical Information section of this website and our engineers are available to help you determine more specific theoretical life calculations.

When should I replace my bearings?

Bearings should be replaced when there is an increase in noise and/or operating temperature or when there is a decrease in running accuracy.

What are some of the modifications you offer?

  • Lubricant of choice
  • Lubrication fitting type or location
  • Seal material and design options
  • Dimensional, both for housings or inserts
  • Set screw options
  • Paint housings to any color

What are the differences between the locking styles you offer?

Detailed information and comparison of our locking styles is available on our website under the product resources drop down menu (Technical Information/Types of Locking).

What types of seals do you offer?

We have four basic sealing arrangements: single lip, double lip, double lip “RF”, and triple lip. Seal information is available on our website under the product resources drop down menu (Technical Information/Seal Material & Design).

Can I add a cover to any type of unit?

No, we cannot add a cover to every single type of bearing unit that we produce, but we have many cover options available, so contact us for recommendations specific to your application.

Can a metric insert fit into an inch housing?

In most cases yes, because the OD of a bearing insert is actually a standardized size, metric size inserts can be put into inch sized housings and vice versa.

Can I use an AMI insert in a competitors housing?

The OD of a bearing is a standardized dimension, so they will usually fit. However the lubrication groove style and location vary widely among bearing manufacturers, so more often than not, mixing components between manufacturers will result in a combination that cannot be relubricated.

How is a bearing mounted properly?

Mounting instructions for all types of our bearings are available on our website under the product resources drop down menu (Mounting Instructions).

What is the maximum allowable angular misalignment allowed with mounted units?

The bearing and the shaft must be aligned within 2° to ensure the bearing can be relubricated by keeping the lubrication hole on the bearing OD in line with the lubrication groove in the bore of the bearing housing. In cases where wider misalignment is necessary, mounted bearing units can operate with up to 5° of misalignment; however they will not be able to be relubricated.

What is the difference between "Dynamic" and "Static" Load Ratings?

Basic Dynamic Load Rating, “Cr” – Is the constant stationary radial load which a rolling bearing could theoretically endure for a basic rating life of one million revolutions.
Basic Static Load Rating, “Cor” – Is the maximum load that can be applied to a non-rotating bearing without permanently damaging the bearing.

Where can I find the load ratings?

The load ratings for all types of our bearings are available on our website and catalogued with the individual bearing insert information.

Why do bearings fail?

  • Too little or too much lubricant
  • Improper lubricant type
  • Poor bearing installation
  • Improper internal clearance
  • Excessive loads and/or speeds
  • Temperature extremes
  • Contamination
  • Movement between mounting surfaces

What causes bearing noise?

Noise coming from a bearing can be caused by one or a combination of several factors such as insufficient operating clearance, excessive operating clearance, change in operating clearance due to temperature, damaged contact areas, contamination, unsuitable lubricant, or damaged raceways.

Why is it important to lubricate a bearing?

A lubricant serves five basic functions to a bearing:

  • Reduce Friction
  • Reduce Wear
  • Reduce Temperature Rise
  • Minimize Corrosion
  • Seal Out Contaminants

Can lubricants be mixed?

We do not recommend mixing greases. Mixing incompatible greases can result in the mixture hardening, preventing it from releasing any of the oil. Mixing incompatible greases can also soften the mixture, which will release all of the oil. Either case will result in a mixture than cannot properly lubricate a bearing. We highly recommend using the same type of grease that was originally supplied with the bearing.

What are AMI standard lubricants?

Standard lubricants supplied with each of our bearings can be found on our website under the product resources drop down menu (Technical Information/Lubrication).

Don't see your question listed here?

Just contact AMI Bearings, Inc. at (800) 882-8642 and we will be happy to assist you.